Internal combustion engine with telescoping pistons



Jan. 25, 1944. R. l.; LANDRY 2,340,064

INTRNAL-COMBUSTION ENGINE WITH TELESCOPING PISTONS Filed sept. 4, 1942 s sheets-sheet 1 R. L. LANDRY 21,340,064 INTERNAL COMBUSTION ENGINE WITH 'IELESCOPING `PISTONS- Jan. 25, 1944.

s sheets-sheet 2 Filed Sept. 4, 1942 Gttorneg Jan. 25, 1944. R. l.. LANDRY INTERNAL COMBUSTION ENGINE'WITH TELESCPING PIISTONS 3 Sheets-Sheet 3 Filed Sept. 4. 1942 lllv SnDentor Cttorneg Patented Jan. 25, 1944 E UNHTED STATES f PATENT y 2,340,064ff 'INTERNAL `cotmtis'rloiv ENGINE WITH TELEscoPmG PIsToNs Rosemond L. Landry, Jackson' Heights', N. Y. vvAppliczttio'n September 4, 1942,-k ScralNo.- 457,334

" 2 claims. m1112915) The present invention relates torim'provements in internal combustion engines and has for an object to provide a construction to obtain incre power per unit of fuel thanis possible withf'internal combustion engines as now constructed creased space for expansion is provided ina'separate compartment or an adjacent cylinder. fin engines Where added space is provided in one cylinder such cylinder has a bore of two diameters and is tted with pistons of two diameters for two compartments in one cylinder. These compartments are separated by a bypass valve,-v

which is placed in a passage connecting the two chambers formed by the twofdiameters ofpist'n and cylinder bore. In engines where anadjapovidefor lvariable expansion ratios by the use of` interchangeable composite telescoping pistons in which the smaller or compression pistons vof the couple' areof different diameters, While maintaining constant the overall ldiameter of the larger external piston section. 1

' The'nvention has for its further purpose and object to provide means for varying the volume and capacity of the compression chamber in step rvIIS cent cylinder is provided forincreased space'for expansion, a bypass valve is aISdrequiredtobe placed in a passage connecting the cylinders. All of these devices require three'valves forthe'ir functioning, the valves being intakevalve, bypass valve and exhaust valve. These 4designs involve a greater expense in construction and are not as eicient as an engine constructed and operating according to my present invention. l Y

In the improved engine only tWdvalves'are required, expansion being connedto thecyli'n der in which the charge-iscompressefd. The increased space for expansion-is providedfb'y means of a two-part telescoping piston functining in upper end of a conventional cylinder.` V'-"Il'ie charge is drawn in and compressed bythe small piston, the large telescoping section oi pistonebeing held at the top end ofithe cylinder byV a detent latch at the end of the compression"v stroke. On the expansion stroke Athe large telescoiiilfig' section or piston is released, from detent latch and descends with compression'piston, tl'1us"`ii'i4 creasing expansion space to area of bore in main cylinder.

A further object of the invention is to 'secure the advantages of an increased expansion ratio in existing forms of engines, and'without changing present engine design, by the simple expedient of substituting for thef standard'v pistona. composite two-part telescoping piston" of the present invention.

It is a stili further object of the invention' teA withV diametric changes in inner piston section.

fWith the foregoing and other objects'in view,

`the invention will be more fully described here-A Y inafter' and more particularly pointed out inthe appended claims. Inithe dravn'ngs, in which like parts `are vdenoted bythe same reference characters throughs 'out the several views,

Fig.v lf'is' a top plan View,v with parts" broken away;l of "an improved engine constructed in accordancewith the present invention.

Fig. 2 is a vertical longitudinal section taken onthe line 2`-2 in Fig. 1.

' Figs. 3, 4, 5, 6 and l are cross sections, all taken onY the" line 3;-3 in Fig. 1 and showing successive positions of piston sections in the various cycles of engine' operation.

"Figsf 8 'and 9 are side elevational views respectivelyof 'separate and integral piston and crosshead assemblies, and

Y Fig.` 10 is a fragmentary `'vertical' section of the cylinder and piston construction illustratinga inc died Aform of detent and operating means.

v:Referring more particularly to theA drawings,

H'r' esnts' a'cylinder block cast in one piece and 'containing any number of 'cylinders desired, 'whicha-re vfwateif-jacketed in the usual manner. Cylinderbore'is uniform indiameter and open atbothf lends, the bottom end of -cylinder acting a guide for the crosshead. The'top end of "for any predetermined ratio of compression at 5o' whichvth engine is to operate, this being important for when this space is relied'on in casting, there is invariably a difference due to unequal casting and to rectify this requires that space be machine `finished to obtain the exact volume manifold I8.

The crankshaft is shown at I9 withits pitma or connecting rod 20. The cam shaft l2 lV 'and'.- its 1o The crank case I1 is of the usual type now in general use, as is also the intake and exhaust,

cams 22 and 23 are in operative relation to .thes

intake and exhaust valves 24'and 25.

downward stroke drawing in the charge. The intake and exhaust valves are closed. The cam 22 .which operates intake valve 24 has its peak 22 in contact with the follower 22b and will open valve 24 as soon as piston starts downward. Detent latch 29 will hold the piston 28 and prevent it from descending with the piston 21. The charge will be drawn into the small cylinder f ,ormedfby the telescoping pistons 21 and 28. While the piston 21 is descending, drawing in the charge,the cam is advancing and holding intake yalve 24 open and allowing charge to be drawn into the bore of piston 28.

At the end of the `mal1'pistcn' 21. stroke, the complete charge will l'lrave been drawn into the bore formed by the telescoping piston 28. The cam has advanced,

Aand itspeak 22a has released the follower 22h,

The connecting rod 20 iscoupled't'oa 'cross head 26, the sides whereof have convex outer surfaces to fit slidably in the base of the'lower' end of the cylinder. The upper part of the crosshead 26 carries the small section 21 'of the twoparttelescoping piston. Such small piston 21 is: 'fitted ,with piston rings atits upper portion to form a working piston reciprocating in .a cylinder bore made inthe outer large piston section 28. The diameter of .the large pistonf28n1'ay be that of the cylinder of a standard formo'f engine. The twopistons constitute a piston-cou: ple, the overall dimensions of which conform -to present standard practice, by which the advantages ofthe invention are available to existing engines without modification save that involved in piston substitution.

:The large -piston telescopes over ton with the small piston21preferably inalinement with the combustion space -l5 inthe cylinder head. Such large piston 28 reciprocates intermittently in the engine cylinder and is` not directly connected to any moving part offthe engine. A.

A spring-projected detent 29 mounted in the cylinder blockv l I is biased to a position in which itsbeveled nose extends beneath the fbeveled lor inclined lower end 35 of the large piston 28;.; The large piston 28 is provided with one or more piston rings forming a working piston in the main cylinder, 'and this large piston is preferably U- shaped in cross section for lightness and cooling.. A flange 36 on the crosshead 2S receives, lsupports and lifts the large piston 28.

The value ofthe spring of the detent 2 5v is such..as,tofh,old the large piston 28`elevated.; at all times except. on the. expansion stroke, when the force of the explosion exceeds this value; A vent' 30 in bottom of cylinder is located so 4that itis notcovered bycrosshead. -.Air entering the.` space yaround vsmall piston l21when telescoping. piston 28 is heldin topposition, becomes heated, and will be forcedpout through vent 30 when large piston 28` descends. Cold air will yb e drawn in when large piston 28 rises. This action will produce a-cooling effect for pistons 21 and 128 in addition kto that obtained from water jacket.V

parts atthe start and end of each stroke. its

thereis no lapse of time between the end of one stroke ,and the beginning of the following stroke,

.it is obvious that the position of the piston is the same at the end of the upward stroke and the Vvstart of the-downward stroke.

'i The operationis as follows: 1 ,1Fig,

the small pis-I and allowed intake valve 24 to close.

Fig. 5 shows the compression stroke about to start, all valves being closed. Piston 21 moves upward inthe smal cylinder formed by the bore in piston 28.' The charge is compressed, cam 22 continuing its. rotation.

--1Fg.- 6, showsthe piston 21 at end of compression stroke. f Combustion is taking place and expansion stroke starts. The pressure from expansion, forces the piston 28 to disengage latch 29 and piston 28-wil1 descend with piston 21, its inner leg resting on the flange 36 at bottom of the piston 21. All pressure from both pistons is transmitted to crank shaft, both pistons descending togethercreating the increased space for expansion of gases. When the pistons reach bottom center, expansion will be complete. The exhaust cam, which is not shown, will bein contact with exhaust ,valve 25 which will open as the pistonsl ,start their upward and exhaust stroke.

, Fig; 7l shows pistons about to start their upward andexhaust stroke. Exhaust valve 25 will open on the upward stroke. Piston 21 will also cause piston 28 to move upward, exhausting the expanded gases through exhaust valve 25. On reachingtop ofy stroke gases will have been expelled. yThe exhaust valve 25 closes and the detentlatch 29reengages piston 28. The four cyclesare completed; all parts are in the position-shown in FigA and another cycle is started. g Figs; 8 and 9 illustrate different modes of constructing the `small piston and crosshead.

A 1 ig .9l shows piston 21 cast integral with crosshead and Fig. 8 shows piston 21 and the crosslhead ,cast separately and united by bolts 31. In changing the Ahorse-power of the improved engine where the type of crosshead and piston shown in Fig. 9is used, the crosshead 23 cast integral with the piston is changed. The type shown in Fig. 8 trequires changing pistons. The crosshead need'not bechanged and is retained. In all types of internal combustion engines, be they of the general type in which the ratio. of

combustion andthe-ratio of expansion is the c5' Figs. 4, 5, 6 and 7' show the positions of.V the expansion than the ratio of compression, such engines when originally constructed have a defi.- nite rated horse-power at their specied ratio of compression. This rated horse-power cannot be changed by substitute parts and any small change that is possible is limited to any change made in compression ratio and alteration to cylinder bore. This would then establish another A definite horse power to the engine and such engine could not be converted back to its original rating.

In the improved engine I can change the horse power to a higher or lower rating in horse power and again change back to its original rating consisting of its original parts and no parts will have been altered. The following explains how this is possible and accomplished.

Referring more particularly to Fig. 10, the shank 3! of the detent latch is exposed outside the cylinder and threaded to receive the adjusting nut 32. This nut forms an adjustable abutment for the engagement of the upper end of the rocker arm 33, the lower end of which is operatively contacted by cam 34 on camshaft 2|. The cam 34 is timed to rock the device mechanically and positively to cause withdrawal of the detent latch at the appropriate time interval, whereby large piston 23 may descend in company with small piston 21 on the expansion stroke. With the use of such a detent, the cylinder 28 is not bevelled, the use of this form of detent control being the preferred form especially for large engines.

It will be particularly noted that combustion chamber l5 has 4a diameter substantially equal to that of the inner piston 21, and this combustion chamber may be increased or decreased in size by the adjustment IS. When the pistons are in the position shown in Figures 4 and 6, the end surfaces of the pistons are flush with each other and all the space between the end of the pistons and outer end wall of the cylinder is closed save for the continuation of the conduit I4. f

The constructions shown and described are illustrative of the best modes known to me of carrying out the principles of the invention, but I do not desire to be restricted to such embodiments, as the invention is susceptible of many other forms. The inventive concept is dened in the following claims.

Having thus described my invention, I claim:

l. In an internal combustion engine having a crankshaft, a cylinder open at the top and bottom, a cylinder head for the top open end of the cylinder having ignition means, a composite piston comprising an expansion part reciprocating in said cylinder and a compression part therein of smaller area, reciprocating independently in said expansion part and coupled to the crankshaft, the faces of the composite piston being ilush with each other during expansion and exhaust, and provided with a releasable detent means to hold the expansion part ush with the inner wall of the cylinder head during intake and compression while said compression part moves out and in on these two strokes, and having a part of said piston reacted upon by the explosion force to permit the expansion part to be driven out with the compression part on the expansion stroke, said detent being released by the pressure of the expansion part acted upon by the combustion pressure, said cylinder head provided with intake and exhaust valves offset from the cylinder bore, the inner wall of the cylinder head being flush with the end of the cylinder and with the faces of the composite piston at the top dead center, a centrally disposed cylindrical opening in said cylinder head having a diameter substantially equal to the diameter of the compression part of the piston and formingr a combustion chamber, a plug for said opening adapted to close the same and to vary the operative space of said combustion chamber to any ratio of compression preselected for the respective areas, and separate channels in the cylinder head connecting said combustion chamber with the intake and exhaust valves respectively, whereby the compression part draws in the charge into the space of the cylinder volume on its down movement, and compresses said charge therein and in the combustion chamber on its return movement, both piston parts being forced downwardly iiush with each other upon disengagement of the detent upon ignition of the charge, and both piston parts moving flush with each other on the return movement to exhaust the charge, the flame travel being confined substantially to a diameter equal to the compression part to complete combustion quicker than When the flame travel is substantially equal to the larger expansion part.

2. The structure of claim 1, in which the lateral walls of the combustion chamber are longitudinally aligned with the interior walls forming the bore in the expansion part and with the exterior walls forming the compression part.

ROSEMOND L. LANDRY. 

